Re: [whatwg] Adding progress event for native <form>?

On Tue, Apr 11, 2017 at 2:44 PM, Mikko Rantalainen
<> wrote:
> I see that already defines ProgressEvent
> for XMLHttpRequest.
> Would it be possible to add "progress", "load", etc. events to normal
> form elements, too? Basically, I would like to do
>   form.addEventListener('progress', function (e) {...})
> and if the end user hits the Submit button, my progress listener would
> get called with ProgressEvent with lengthComputable, loaded and total
> attributes.
> If I have understood correctly, this does not make any information
> available to JavaScript that is not already available because JavaScript
> *can* already evaluate all form fields, use FileReader API to get all
> the files in file inputs and submit the form to the same action URL
> using XMLHttpRequest. In addition, browsers already implement all the
> required code because XMLHttpRequest needs that behavior.
> If listening for "progress" were allowed, I could implement my own form
> submission UI and still use regular forms that would work even without
> JavaScript.

It would leak new information cross-origin and due to redirects that
would be hard to distinguish from same-origin. You'd also have to
submit into some kind of <iframe> as otherwise you end up navigating


Received on Tuesday, 11 April 2017 13:06:14 UTC